from time import sleep,ctime
import threading

loops = [4,2]

def loop(nloop,nsec):
    print('start loop ',nloop, 'at:',ctime())
    sleep(nsec)
    print('loop ',nloop, 'done at:',ctime())

def main():
    print('starting at:',ctime())
    threads = []
    nloops = range(len(loops))

    for i in nloops:
        lock = threading.Thread(target=loop,args=(i,loops[i]))
        threads.append(lock)

    for i in nloops:
        threads[i].start()
    
    for i in nloops:
        threads[i].join()
    print('all Done at:',ctime())

if __name__=='__main__':
    main()